Akani Simbine became the first south african sprinter to run sub 10 (9.93 s) and sub 20 (19.95 s) at 100/200 m the same day and i think there are not too many guys in history running sub 10 and sub 20 in their career. 18 year old Clarence Munyai from South Africa ran 20.10 s (200 m) recently and is now the 5th fastest U20 athlete ever, only 0.17 s away from Usain Bolt's junior world record. South Africa is extremely impressive in mens sprint (100/200/400 m) and it also shows in mens long jump. I dont know what happened in Rio with their relay, but if they dont completely mess up in London, they should win a medal with Simbine, Jobodwana, Van Niekerk and one of their young guys (Munyai, Leotlela). I think we have very exciting times ahead and the american/jamaican dominance might be ended by Japan/South Africa. GB, Canada, Germany and China also should have pretty fast relays for the next couple of years, so mens 4 x 100 m relay might be one of the most competitive events in athletics and probably all sports.